Configurable flip-flop cells for use in scan chain configurations include one or more multiplexers, a flip-flop, and one or more logic gates. The logic gates are configurable, through modification of different metallization or semiconductor layers, to operate as spare gates or to disable flip-flop cell outputs based selection signal switching between scan shift and capture mode. When disabling flip-flop cell outputs, the logic gates are configured to receive both a test signal and a data input signal and select one of the two to pass to the flip-flop based on the selection signal. When used as spare gates, the logic gates receive external inputs and provide spare gate outputs to circuitry on an integrated circuit that is external to the flip-flop cells.